This invention relates generally to building materials and, more particularly, to a silicone rubber composition useful for building purposes and building elements formed from such composition.
Silicone rubber compositions have been used as waterproofing materials for a variety of applications such as providing a waterproof coating for existing building roofs. Silicone rubbers have also been extensively used in other applications because they are generally unaffected by wide temperature variations and resist the deteriorating effects of acids, bases, salts and UV radiation. An example of one such application is disclosed in my previous U.S. Pat. No. 4,297,265 which discloses the application of a solubilized silicone rubber and silicon dioxide composition onto flexible substrates such as glass cloth for use as awnings or other flexible building structures. Other uses of silicone rubber are disclosed in U.S. Pat. Nos. 2,751,314, 2,934,464, 2,979,420 and 3,455,762.
Roofing elements such as shingles can be made from a variety of materials such as tile, slate, wood, concrete and compositions of asphalt and aggregate. All of such materials experience weathering to varying degrees, with the relatively inexpensive asphalt composition shingles and commercial roofing typically being the most affected by prolonged exposure to UV radiation, temperature variations and other environmental conditions. Wood shingles are generally more durable than composition shingles and are more aesthetically pleasing. However, because of the flammability of wood shingles they have been banned in many areas as a fire hazard. Clay tile and slate roofs present little if any fire risk but are so expensive that they have not experienced widespread usage. Concrete shingles are extremely durable and fire resistant but are heavy in comparison to other types of materials. Concrete shingles also readily absorb water because of their porous nature, further adding to the load which must be supported by the structural elements of the roof. It can thus be seen that a need exists for a shingle or roofing element which is lightweight, fire and water resistant, and capable of withstanding the effects of weathering over a prolong time period.
Likewise, building elements such as flooring, blocks, beams, and other structural elements are made from a variety of materials such as concrete, wood, steel and the like. Each of these conventional materials has advantages as well as significant disadvantages. For example, steel provides a very high strength material for a use as structural beams, but the beams must be coated with a fireproof material because the beam is subject to failure when exposed to high temperatures. Moreover, the fireproofing material typically contains asbestos which has been shown to present a significant health risk. Wood is widely used for various building elements because it is inexpensive and provides satisfactory strength for many applications. Wood, however, is readily combustible and is subject to rot and insect damage. Reinforced concrete provides high strength structural elements but is heavy and can be significantly weakened by exposure to moisture which causes rusting of the metal reinforcing bars. A need thus exists for lightweight building elements which are fire and water resistant, generally impervious to rot or insect damage and are of sufficient strength for the desired applications.